
package net.swa.index.web.action;

/**
 * 提供火星坐标系统 GCJ-02  纠偏
 * 
 * @author Administrator
 * 
 */
public class MapAction extends AbstractBaseIndexAction
{
    private static final long serialVersionUID = 1L;

    final static double pi = 3.14159265358979324;

    final static double a = 6378245.0;

    final static double ee = 0.00669342162296594323;

    private double lat, lng;

    public String transform() throws Exception
    {
        double rlat;
        double rlng;
        if (outOfChina(lat, lng))
        {
            rlat = lat;
            rlng = lng;
            outString("{\"lng\":" + rlng + ",\"lat\":" + rlat + ",\"error\":1}");
            return null;
        }
        double dLat = transformLat(lng - 105.0, lat - 35.0);
        double dLon = transformLon(lng - 105.0, lat - 35.0);
        double radLat = lat / 180.0 * pi;
        double magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        rlat = lat + dLat;
        rlng = lng + dLon;
        outString("{\"lng\":" + rlng + ",\"lat\":" + rlat + ",\"error\":0}");
        return null;
    }

    private static boolean outOfChina(double lat , double lon)
    {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }

    private static double transformLat(double x , double y)
    {
        double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    private static double transformLon(double x , double y)
    {
        double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }

    public double getLat()
    {
        return lat;
    }

    public void setLat(double lat)
    {
        this.lat = lat;
    }

    public double getLng()
    {
        return lng;
    }

    public void setLng(double lng)
    {
        this.lng = lng;
    }

}
